#!/usr/bin/env bash
# Zeus self-hosted installer bootstrap.
#
# Kept tiny and portable on purpose (design doc: build-plan/13-self-hosted-install.md).
# All real logic lives in the zeus-install Go binary this script downloads and
# execs; this script only does what a static binary can't do for itself:
#   - detect distro + arch
#   - install Docker engine + compose plugin if missing (get.docker.com)
#   - enable docker on boot
#   - download the right zeus-install binary and exec it, forwarding argv +
#     stdin from the real terminal (so prompts still work under `curl | bash`)
#
# Usage: curl -fsSL https://get.zeusk8s.com/install.sh | bash -s -- [zeus-install flags]

set -euo pipefail

BASE_URL="${ZEUS_INSTALL_BASE_URL:-https://get.zeusk8s.com}"

log() { printf '==> %s\n' "$*" >&2; }
die() { printf 'error: %s\n' "$*" >&2; exit 1; }

# --- arch detection -----------------------------------------------------

detect_arch() {
	case "$(uname -m)" in
		x86_64|amd64) echo amd64 ;;
		aarch64|arm64) echo arm64 ;;
		*) die "unsupported architecture $(uname -m) (zeus-install supports amd64/arm64 linux only)" ;;
	esac
}

# --- distro detection (informational + docker-install branch) ----------

detect_distro() {
	if [ -r /etc/os-release ]; then
		# shellcheck disable=SC1091
		. /etc/os-release
		echo "${ID:-unknown}"
	else
		echo unknown
	fi
}

# --- tty helpers (curl | bash means stdin is the script, not a terminal) --

tty_prompt_yes_no() {
	local prompt="$1" default="${2:-n}" ans
	if [ ! -e /dev/tty ]; then
		echo "$default"
		return
	fi
	printf '%s [y/N]: ' "$prompt" > /dev/tty
	read -r ans < /dev/tty || ans=""
	case "$ans" in
		y|Y|yes|YES) echo y ;;
		*) echo "$default" ;;
	esac
}

# --- docker install ------------------------------------------------------

docker_present() {
	command -v docker >/dev/null 2>&1 && docker compose version >/dev/null 2>&1
}

install_docker() {
	log "Docker (with the compose plugin) was not found."
	if [ "$(tty_prompt_yes_no 'Install Docker now via get.docker.com?' y)" != "y" ]; then
		die "Docker is required. Install it yourself, then re-run this installer."
	fi
	log "installing Docker via get.docker.com ..."
	curl -fsSL https://get.docker.com | sh
	if command -v systemctl >/dev/null 2>&1; then
		systemctl enable --now docker
	fi
}

# --- main -----------------------------------------------------------------

main() {
	local arch distro skip_docker=0 arg
	arch="$(detect_arch)"
	distro="$(detect_distro)"
	log "detected linux/${arch} (${distro})"

	# --skip-docker-install is also a zeus-install flag (forwarded below as-is);
	# recognize it here too so the bootstrap doesn't install Docker only to
	# have the operator not want that.
	for arg in "$@"; do
		[ "$arg" = "--skip-docker-install" ] && skip_docker=1
	done

	if [ "$skip_docker" != "1" ] && ! docker_present; then
		install_docker
	fi
	if command -v systemctl >/dev/null 2>&1; then
		systemctl enable --now docker >/dev/null 2>&1 || true
	fi

	local bin_url tmp_bin
	bin_url="${BASE_URL}/bin/zeus-install-linux-${arch}"
	tmp_bin="$(mktemp -t zeus-install.XXXXXX)"
	trap 'rm -f "$tmp_bin"' EXIT

	log "downloading ${bin_url}"
	curl -fsSL -o "$tmp_bin" "$bin_url"
	chmod +x "$tmp_bin"

	log "starting zeus-install"
	if [ -e /dev/tty ]; then
		exec "$tmp_bin" "$@" < /dev/tty
	else
		exec "$tmp_bin" "$@"
	fi
}

main "$@"